Phase behaviour of a diglyceride prodrug: Spontaneous formation of unilamellar vesicles

摘要: Abstract A prodrug (Fig. 1(IV)) is synthesized consisting of the β-blocker bupranolol which covalently linked to 1, 3-dipalmitoyl-2-succinyl-glycerol. The resulting lipid-like amphipathic and surface active. It disperses readily in H 2 O above 30°C forming a smectic lamellar phase. This bears one positive charge at neutral pH hence swelling behaviour dispersions similar that charged phospholipids: show continuous with increasing water content consequently excess region phase diagram thermodynamically most stable structure unilamellar vesicle. includes oligomeric vesicles may be defined as containing smaller, also entrapped their internal aqueous compartment. are polydisperse vesicle sizes ranging from 0.1 μm several μm. Sonication these produce small an average size distribution sonicated egg phosphatidylcholine dispersions. Unsonicated undergo reversibly sharp order-disorder transitions 32°C enthalpy change ΔH = 10 kcal/mol. In this transition asymmetric significantly broadened indicating cooperativity markedly reduced. peak temperature broad reduced compared observed unsonicated dependence electron spin resonance (ESR) hyperfine splitting order parameter reflects transition. From ESR labeling it concluded molecule more mobile its anisotropy motion result indicates molecular packing highly curved bilayers perturbed